It is well-known that the overexpression of the HER family of receptors, for example HER1 (EGFR), HER2, HER3, and HER4 receptors, in a cell leads to strong and constant proliferative signaling in the cell, which ultimately leads to the development of certain types of cancer, for example breast cancer. HER2-positive breast cancers represent almost a quarter of invasive breast cancers and are indicative of poor patient survival. Trastuzumab is a monoclonal antibody that interferes with the HER2/neu receptor. It is currently marketed under several trade names, such as Herceptin®, for the treatment of certain breast cancers. Pertuzumab is another monoclonal anti-HER2 antibody, which is used in cancer treatment. Lapatinib is a small molecule organic compound that exerts a therapeutic effect in breast cancer. These therapies are generally used as a last line defense against cancer, after other therapeutic regimens have failed. Unfortunately, although many patients with HER2-positive breast cancer initially respond to these anti-HER2 treatments, a significant portion of them develop resistance to these therapies. Once resistance to a late stage therapeutic is developed, the options for the treatment become very few indeed. Consequently, there is a great need to develop new drugs that are effective against these HER2+ tumors that are non-responsive or have become resistant to these therapies.